Don't be frightened by sharks: you are 30 times more likely to be hit by lightning than be attacked by a shark.

　　The wonderful world of pigeons

　　It is night. All is quiet. The soldiers are asleep while a guard watches for the enemy. There is a flash, and the sound of guns! They are being attacked! Hundreds of enemy soldiers rush towards them. They are all going to be killed unless they get help. What should they do?

　　An officer writes a short message quickly on a small piece of paper: 'Being attacked! Hurry！'

　　He rolls up the paper and puts it into a small case, and then reaches into a cage and gets a bird. Attaching the message to its leg, he sets the bird loose. It immediately flies into the air and disappears in the dark.

　　Will the bird arrive in time? Will they be saved?

　　Though it may seem hard to believe, the bird the officer uses is the same bird often seen in public parks - the pigeon. Pigeons have a wonderful sense of direction and can find their way home over long distances. Indeed, pigeons have been known to fly home from as far away as 1,800 kilometres. That is why pigeons have been used since ancient times to carry the news or even the mail. However, it was in war that they found their greatest use. During both World War Ⅰ and Ⅱ， pigeons were employed by armies to carry messages to and from the front lines, saving the lives of many soldiers and even helping win some important victories.

　　How do pigeons find their way? Pigeons appear to have a compass inside them that tells them which way is north. How this compass works remains a mystery. Of course, since a compass alone is not enough to find one's way, they also appear to use their sight and even their sense of smell to tell them which way they should go.Unlike humans, they never get lost and can always find their way home.

　　鲨鱼的攻击

　　有将近400种不同种类的鲨鱼，但人们所知的攻击人类的鲨鱼仅有约30种。许多人都知道最危险的鲨鱼是大白鲨，可能是因为他们看过电影《大白鲨》。然而，还有其他两种危险的鲨鱼，它们是虎鲨和公牛鲨。

　　和人们所猜想的相反，有证据表明鲨鱼很少攻击人类。鲨鱼(对人类)的攻击有三种方式。在主要的情形中，鲨鱼攻击你是因为它把你错当成了鱼，但当它发觉是人肉的味道时，就会决定放弃并游开。在第二种情形中，鲨鱼会用鼻子推搡你，以弄清你是否适合被食用，如果它觉得适合，便会咬你。在第三种攻击中，鲨鱼只等你游过它身边，随即猛地发起攻击。后两种攻击方式经常导致人类的死亡。

　　为了减少被攻击的危险，你应谨遵以下建议：

　　·不在黑暗处游泳。(在黑暗处)鲨鱼可以看见你，而你无法看见它们。

　　·如果你有新伤口，就不要在海里游泳。即使隔着很远的距离，鲨鱼仍能嗅到血腥味。

　　·不要穿鲜亮的服装或佩戴珠宝，因为色彩和发光的物体对鲨鱼很有吸引力。

　　·和大家待在一起，因为鲨鱼通常会避开人群。

　　最近，随着水上运动越来越受人们青睐，鲨鱼攻击(人类的事件)也在持续增长。如果遭到鲨鱼攻击，请尝试以下一些建议进行自救：

　　·保持镇静不要惊慌失措。

　　·用拳头击打鲨鱼的鼻子。

　　·用手指戳鲨鱼的眼睛。

　　不要惧怕鲨鱼：你被闪电击中的几率要比遭受鲨鱼攻击的几率大30倍。

　　鸽子的奇妙世界

　　万籁俱寂的夜晚，除了警卫员在监守敌军外，所有士兵都已睡去，突然传过枪声和火光，他们被偷袭了！数百敌军向他们冲来。除非他们得到援助，否则他们将面临死亡。他们应该怎么办？

　　一个军官在一张纸片上迅速写下简短的信息："被偷袭！赶快支援！"

　　他把纸片卷起来，放进一个小盒子里，然后伸手探入一个笼子里，捉出一只鸟来。把信息系到它的腿上，然后把鸟放飞。它立刻飞向高空消失在黑暗中。

　　那只鸟能否及时到达？他们会得救吗？

虽然这似乎令人难以置信，但那名军官所用的鸟儿和我们常在公园里看到的一种鸟是